This invention relates to electrical circuits for generating sparks for firing explosives and the like and, in particular, to a new and improved monostable multi-vibrator circuit for generating an electric spark between spaced electrodes for igniting a solid explosive, such as would be used in a firearm for propelling a projectile.
Battery powered oscillator circuits have been used in the past for producing electric arcs between electrodes. See U.S. Pat. Nos. 3,671,805; 3,731,144; and 4,141,297. An improved circuit is shown in U.S. Pat. No. 4,355,263. However during operation and testing of the circuit of the later patent, some disadvantages have been noted. While the circuit does operate, it has been difficult to obtain the desired high output voltage. Also problems were encountered with component burn out, and the operation was sometimes erratic.
Accordingly, it is an object of the present invention to provide a new and improved ignition circuit. It is a particular object to provide such a circuit which has reduced I.sup.2 R losses and one which will provide output voltages in the order of 12 kilovolts at an electrode spacing of 0.06 inches.
Another object of the invention .sbsp.it to provide such a circuit utilizing a conventional integrated circuit chip and a conventional switching transformer. In particular, it is an object of the invention to provide such an ignition circuit utilizing a monostable multi-vibrator rather than a free running multi-vibrator, and a circuit which provides for setting of pulse width as desired for the particular material to be ignited.
Other objects, advantages, features and results will more fully appear in the course of the following description.